Safety device

ABSTRACT

A safety device is disclosed which is configured to be actuated by the supply of gas. The safety device incorporates an outlet vent pipe which is sealed by a releasable clip. The releasable clip has a first elongate main gripping element and a second elongate moveable gripping element. The main gripping element has a retaining element to retain one end of the moveable gripping element. The safety device also includes an arrangement to retain the other end of the moveable gripping element in a predetermined position such that the clip may grip a fabric tube or the like between the main gripping element and the moveable gripping element. A mechanism is provided which responds to a supply signal to move the other end of the moveable gripping element to release the grip.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to GB 0305164.6, filed Mar. 6,2003 and GB 0400779.5, filed Jan. 14, 2004 which are currently pending.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to a safety device.

[0003] It has been proposed to provide various forms of safety device toprovide protection for an occupant of a vehicle in the event that anaccident should occur. For example, various types of air-bag have beenproposed which, depending upon their design, may occupy many differentpositions within a vehicle relative to a driver. When an air-bag is tobe deployed, a gas generator is actuated which generates gas whichserves to inflate the air-bag.

[0004] In some cases it is desirable for the pressure in the air-bag tobe controlled and/or for the air-bag to be “vented”, especially if theoccupant has a weight which is not typical, either being relativelyheavy or being relatively light, or, alternatively, if the occupant is“out of position” (for example leaning forwardly).

[0005] Various proposals have been made for mechanisms to ventilate anair-bag including controlled valves, burst discs and tear-seams whichinitially seal an outlet air vent. Sophisticated arrangements mayinclude elements such as pressure sensors and/or control units todetermine the weight and the position of an occupant and to control theopening of a gas exhaust valve in an optimal manner.

[0006] However, there is a requirement for a simple device to controlthe ventilation of an air-bag which can be used in a flexible manner toprovide ventilation at different positions within an air-bag.

[0007] Other safety devices also rely on generated gas, such aspre-tensioners, and there is a requirement for a mechanism that may beutilised to control the operation of such safety devices.

[0008] Accordingly, to a first aspect of the present invention, there isprovided a safety device in the form of a releasable clip, thereleasable clip having a first elongate main gripping element, and asecond elongate moveable gripping element, the main gripping elementhaving a retaining element to retain one end of the moveable gripingelement; there being an arrangement to retain the other end of themoveable gripping element in a predetermined position such that the clipmay grip a fabric tube or the like between the main gripping element andthe moveable gripping element; a mechanism being provided which respondsto a supply signal to move the other end of the moveable grippingelement to release the grip.

[0009] According to another aspect of the present invention, there isprovided a safety device configured to be actuated by the supply of gas,the safety device incorporating an outlet vent pipe, the outlet ventpipe being sealed by a releasable clip, the releasable clip having afirst elongate main gripping element, and a second elongate moveablegripping element, the main gripping element having a retaining elementto retain one end of the moveable gripping element; there being anarrangement to retain the other end of the moveable gripping element ina predetermined position such that the clip may grip the outlet ventpipe or the like between the main gripping element and the moveablegripping element; a mechanism being provided which responds to a supplysignal to move the other end of the moveable gripping element to releasethe grip.

[0010] Preferably, the safety device is an air-bag.

[0011] Advantageously, the safety device is a pretensioner.

[0012] Conveniently, a plurality of said releasable clips are provided,each clip being associated with a respective outlet hose.

[0013] Preferably, the releasable clip incorporates a spring initiallyheld in a compressed state and released in response to the signal so asto move the other end of the moveable retaining element.

[0014] Advantageously, the main gripping element is in the form of acylinder, and the other end of the elongate moveable gripping element isconfigured to fit over or within the cylinder; there being a mechanismto supply gas to the interior of the cylinder in response to the signalto move the other end of the moveable gripping element.

[0015] Conveniently, the other end of the moveable gripping element isconstituted by a piston movable within the cylinder.

[0016] In one embodiment the cylinder has a terminal inward projectionto retain the piston in the cylinder.

[0017] Preferably, the other end of the moveable gripping elementcomprises a closure cap dimensioned to close an open end of thecylinder.

[0018] Advantageously, the source of gas is a pyrotechnic squib.

[0019] Alternatively, the source of gas is a source of compressed gas.

[0020] Preferably, the moveable gripping element is provided with anelongate cylindrical gripping portion, one end of which is engaged in aretaining lug provided on the main gripping element.

[0021] Advantageously, the main gripping element is in the form of acylindrical housing, and the moveable gripping element has inclinedresiliently mounted walls to engage the exterior of the cylindrical maingripping element.

[0022] In order that the invention may be more readily understood, andso that further features thereof may be appreciated, the invention willnot be described, by way of example, with reference to the accompanyingdrawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]FIG. 1 is a perspective view of a pyrotechnic clip unit;

[0024]FIG. 2 is an end view of the unit of FIG. 1;

[0025]FIG. 3 is a sectional view, on an enlarged scale, taken on theline A-A of FIG. 2;

[0026]FIG. 4 is a view showing the clip unit of FIGS. 1 to 3 mounted onan outlet duct of an air-bag;

[0027]FIG. 5 is a view corresponding to FIG. 4 showing the clip unitwhen released;

[0028]FIG. 6 is a view corresponding to FIG. 1 illustrating a modifiedembodiment of the invention;

[0029]FIG. 7 is a view illustrating an air-bag in a motor vehicleprovided with a pyrotechnic clip unit of the type described above duringinflation of an air-bag;

[0030]FIG. 8 is a view corresponding to FIG. 6 showing the clip unitwhen released, and

[0031]FIG. 9 is a perspective view of an alternative form of clip unitin accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0032] Turning initially to FIGS. 1 to 3 of the accompanying drawings, apyrotechnic clip unit 1 is illustrated, the pyrotechnic clip unit beingconfigured so that, when in use, it may close an outlet hose or duct,formed of a material such as fabric, forming part of an air-bag orforming part of another safety device.

[0033] The clip 1 comprises an elongated hollow cylindrical housing 2which forms a main gripping element, one end of the housing beingprovided with an integral deflected retaining bracket 3 in the form of alug. The retaining bracket 3 defines a “U”-shaped slot 4 which opensinto one side edge of the retaining bracket 3.

[0034] The end of the hollow cylindrical housing 2 provided with theretaining bracket 3 receives a pyrotechnic squib 5 which is held by acrimp 6 as illustrated most clearly in FIG. 3. The pyrotechnic squib 5contains a pyrotechnic charge and is associated with two electrodes 7which are accessible from the open end of housing 2. A plug may beconnected to the electrodes 7. When a current passes between theelectrodes 7, the pyrotechnic squib 5 is ignited to generate asubstantial quantity of gas.

[0035] A moveable gripping element 8 is provided, the gripping element 8including a elongated cylindrical gripping section 9 having a terminalregion 10 configured to be received within the “U”-shaped slot 4 formedin the retaining bracket 3. The other end of the gripping section 9 isprovided with a 180° bend 11 which connects the gripping section 9 to apiston 12 which is dimensioned to be received, as a sliding fit, withinthe hollow tube 2. The piston 12 may have a semi-spherical head so as toprovide a substantially sealing fit even if the piston is not preciselyaligned with the longitudinal axis of the hollow cylindrical housing 2.

[0036] Referring now to FIG. 4, the clip 1 of FIGS. 1 to 3 is shown inposition on the terminal part of a tube 13 which may be a fabric tubeextending from an air-bag to constitute a gas vent, or which may be afabric tube extending from part of some other safety device which isdeployed by the generation of gas.

[0037] It will be understood that the terminal part of the tube 13 hasbeen located in position generally between the cylindrical housing 2 andthe gripping section 9 of the moveable gripping element 8. The terminalpart 10 of the gripping section 9 has been manipulated to be receivedwithin the “U”-shaped slot 4 of the retaining bracket 3, thus firmlytrapping the fabric of the tube 13 between the gripping section 9 of themoveable gripping element 8, and the outer surface of the cylindricalhousing 2. The clip 1 thus forms a substantially air-tight seal at theend of the tube 13.

[0038] Should an appropriate electrical signal be supplied to theelectrodes 7, the pyrotechnic squib 5 will be ignited generating asubstantial quantity of gas within the cylinder 2. The gas will act onthe piston 12 moving the piston 12 axially of the cylindrical housing 2,and thus withdrawing the terminal part 10 of the moveable grippingelement 8 from the “U”-shaped slot 4 formed in the retaining bracket 3.The moveable gripping element 8 thus moves relative to the main grippingelement formed by the housing 2. Indeed, the entire gripping element 8may, as shown in FIG. 5, become totally separated from the cylindricalhousing 2. Thus the tube 13 is no longer retained in a sealed conditionand gas may escape from the air-bag through the tube 13.

[0039] It is to be understood that a number of clips of the typedescribed above may be provided on a typical air-bag at a number ofdifferent positions, and the actuation of the clips may be controlled byan appropriate control arrangement associated with appropriate sensors.Consequently a number of the described clips may be provided on variousgas ducts 13 forming part of a single air-bag, and one or more of theclips may be released. If more than one clip is released, the clips maybe released at appropriate times during an accident situation, independence upon the particular circumstances of an accident involving avehicle in which the air-bag is mounted.

[0040] Whilst, in the above-described embodiment of the invention, themovable gripping element may, as shown in FIG. 5, become totallyseparated from the cylindrical housing, in some circumstances this maybe undesirable. The gripping element 8 may, if it leaves the cylindricalhousing with a substantial velocity, act as a projectile which may beextremely undesirable.

[0041] Thus, in the embodiment of FIG. 6, a terminal part of thecylindrical housing 2, at the end remote from the pyrotechnic squib 5, aprojection which extends radially inwardly is provided, in the form of aflange 14. The flange 14 may be a flange which extends totally aroundthe open end of the cylindrical housing 2, or may be a flange whichextends only part-way around the end of the housing. The flange may bereplaced by an inwardly directed crimp located adjacent the end of thehousing. The flange, or crimp, form a terminal inwardly directedprojection which prevents the piston 12 from escaping from within thecylinder. Thus the piston 12 is retained within the cylinder 2,preventing the gripping element 8 from becoming a projectile.

[0042] Referring now to FIGS. 7 and 8, merely by way of an example, anair-bag 20 in the form of a so-called “inflatable curtain” isillustrated, the air-bag 20 having a forwardly extending restrainingstrap 21 which is in the form of a hollow tube in fluid communicationwith the invention of the main part of the air-bag 20. The free end ofthe tube is receive within a clip 1 as descried above, the cylindricalhousing 2 of the clip 1 being securely fastened to the “A”-Post 22 ofthe illustrated vehicle. Thus the clip 1 seals the tubular strap 21 andalso anchors the end of the strap in position.

[0043] In ordinary deployment of the inflatable curtain, gas will beinjected into the inflatable parts of the inflatable curtain, but willnot be able to escape through the tubular strap 21, because the tubularstrap 21 is maintained closed by the action of the clip 1. The clip 1also holds the tubular restraining strap 21 securely in position.

[0044] Should a particular set of circumstances arise, in which it isappropriate to release the restraining strap 21 and deflate thedeflatable curtain, the clip 1 may be released, in the manner describedabove, by actuating the pyrotechnic squib 5, as shown in FIG. 7, thusreleasing the end of the tubular restraining strap 21 permitting gas toescape from the inflated interior of the inflatable curtain 20 throughthe thus released tubular strap 21, as shown in FIG. 7.

[0045] Whilst the invention has been described above with reference toone form of releasable clip, FIG. 9 illustrates a modified form ofreleasable clip. The clip of FIG. 9 includes a hollow tubular housing 30forming a main gripping element and having, at one end, a deflectedretaining bracket 31 in the form of a lug which defines a squareaperture 32. Received within that end of the tubular housing 31 is asquib 33 corresponding to the squib 5 as described above.

[0046] Associated with the housing 30 is a moveable gripping element 34.The moveable gripping element 34 is formed of a pressed sheet metalplate, the pressed plate defining two inwardly directed opposedresiliently mounted walls 35, 36 having a substantially “V”configuration, the lower ends of the walls being interconnected by a“U”-shaped trough 37. At one end, the trough 37 extends axially to forma projection 38. The projection 38 is dimensioned to be received withinthe square aperture 32 in the retaining bracket 31. At the other end,the trough 37 carries an upstanding support 39 which extends up betweenthe walls 35, 36, and which carries a closure cap 40 dimensioned to fitover and close, in a sealing manner, the open end of the housing 30remote from the squib 33.

[0047] It is to be appreciated that the moveable gripping element 34 isso configured that when the projection 38 of the trough 37 is receivedwithin the aperture 32, the closure cap 40 sealing closes the end of thehousing 30 remote from the squib 33, and the walls 35, 36, due to theirown resilient mounting, are biased against the exterior of the housing30.

[0048] It will be appreciated that the clip may be mounted on a hose,equivalent to the tube 13 as shown in FIGS. 4 and 5, with the hose beingpartly wrapped around the cylindrical housing 30, and with the hosebeing gripped by the two resiliently biased walls 35, 36. The engagementof the projection 38 within the aperture 32, and the engagement of thesealing cap 40 with the end of the housing 30 ensures that the moveablegripping element 34 remains in position. Should, however, an electriccharge be applied to the pyrotechnic squib 5, a substantial quantity ofgas will be injected into the interior of the hollow housing 30, thusdriving the sealing cap 40 away from the end of the housing 30 remotefrom the squib 33, consequently serving to withdraw the projection 38from the aperture 32, and releasing the moveable gripping element 34from the housing 30.

[0049] Whilst the invention has been described with specific referenceto clips in which gas is generated by a pyrotechnic squib in response toa signal, it is to be understood that in a modified embodiment, insteadof using the squib, a source of compressed gas that is opened by asignal may be used, or even a clip that includes a spring which isretained in a compressed state and released in response to a signal torelease the clip.

[0050] The features disclosed in the foregoing description, or thefollowing claims, or the accompanying drawings, expressed in theirspecific forms or in terms of a means for performing the disclosedfunction, or a method or process for attaining the disclosed result, asappropriate, may, separately, or in any combination of such features, beutilised for realising the invention in diverse forms thereof.

1. A safety device including a releasable clip, the releasable cliphaving an elongated main gripping element, and an elongated moveablegripping element having a first and second ends, the main grippingelement having a retaining element to retain the first end of themoveable gripping element; the main gripping element retaining thesecond end of the moveable gripping element in a predetermined positionsuch that the clip may grip a fabric tube or the like between the maingripping element and the moveable gripping element; a gas generatorbeing provided which responds to a supply signal to move the second endof the moveable gripping element to release the grip.
 2. A safety deviceaccording to claim 1 further comprising an outlet duct, the outlet ductbeing sealed by the releasable clip.
 3. A safety device according toclaim 1 wherein the safety device includes an air-bag.
 4. A safetydevice according to claim 1 wherein the safety device includes apretensioner.
 5. A safety device according to claim 1 wherein aplurality of the releasable clips are provided, each of the clips beingassociated with a respective outlet duct.
 6. A safety device accordingto claim 1 wherein the main gripping element is in the form of a hollowcylinder, and the second end of the elongated moveable gripping elementis configured to fit over or within the hollow cylinder; there being agas generator supplying gas to the interior of the hollow cylinder inresponse to the supply signal to move the second end of the moveablegripping element.
 7. A safety device according to claim 6 wherein thesecond end of the moveable gripping element is a piston moveable withinthe hollow cylinder.
 8. A safety device according to claim 7 wherein thehollow cylinder has a terminal inward projection to retain the piston inthe hollow cylinder.
 9. A safety device according to claim 7 wherein thesecond end of the moveable gripping element comprises a closure capdimensioned to close an open end of the hollow cylinder.
 10. A safetydevice according to claim 1 wherein the gas generator is a pyrotechnicsquib.
 11. A safety device according to claim 1 wherein the gasgenerator is a source of compressed gas.
 12. A safety device accordingto claim 1 wherein the first end of the gripping element and theretaining element comprises a retaining lug provided on the maingripping element.
 13. A safety device according to claim 1 wherein themain gripping element is in the form of a cylindrical housing, and themoveable gripping element has inclined resiliently mounted walls toengage the exterior of the cylindrical housing of the main grippingelement.
 14. A releasable clip for a safety device, the releasable clipincluding a main gripping element in the form of an elongated hollowcylinder defining a first and second end, the main gripping elementfirst end having a retaining bracket, and the second end of the maingripping element being opened, a moveable gripping element having afirst and a second end, the first end of the moveable gripping elementreceived by the retaining bracket, the second end of the moveablegripping element obstructing the second opened end of the main grippingelement, a gas generator in the hollow cylinder, the releasable clip ina first predetermined position gripping a duct of the safety devicebetween the main gripping element and the moveable gripping element, andin response to a supply signal supplying gas within the hollow interiormoves the moveable gripping element second end disengaging the moveablegripping element second end from the retaining bracket to release thegripping of the duct.
 15. A safety device according to claim 14 whereinthe safety device includes an air-bag.
 16. A safety device according toclaim 14 wherein the safety device includes a pretensioner.
 17. A safetydevice according to claim 14 wherein a plurality of the releasable clipsare provided, each of the clips being associated with a respectiveoutlet duct.
 18. A safety device according to claim 14 wherein thesecond end of the moveable gripping element is a piston moveable withinthe hollow cylinder.
 19. A safety device according to claim 18 whereinthe hollow cylinder has a terminal inward projection to retain thepiston in the hollow cylinder.
 20. A safety device according to claim 14wherein the second end of the moveable gripping element comprises aclosure cap dimensioned to close an open end of the hollow cylinder. 21.A safety device according to claim 14 wherein the gas generator is apyrotechnic squib.
 22. A safety device according to claim 14 wherein thegas generator is a source of compressed gas.
 23. A safety deviceaccording to claim 14 wherein the main gripping element is in the formof a cylindrical housing, and the moveable gripping element has inclinedresiliently mounted walls to engage the exterior of the cylindricalhousing of the main gripping element.